Confirming structure of aspartic acid at PH 4

[n.a.s.h]

Homework Statement

Draw the structure of aspartic acid at PH 4. I calculated the PI and based on that, drew the
charged structure. If anyone can confirm that this is the correct structure.

Homework Equations

The Attempt at a Solution

I attached the structure. Thanks for any assistance.

 

[Borek]

At pH 4 solution contains about 62% of -1 form, and around 37% of neutral form. But I doubt -1 form is the one you have drawn, I don't think proton is on the amine group.